I was at a shop once that did a lot of chassis fabrication. He got one of those files, and then ordered two of every pre-made bracket and tab from a couple different chassis parts suppliers, painted the part number on them and put them in the drawer. When he was fabricating a chassis for a customer, he'd go to his big cabinet full of brackets and tabs, find the ones he needed, mock them up, then order the number he needed from the supplier.
I always thought that was pretty cool.
They'd make good drawers for machine tool cutting bits as well.
-Brad